The document also identified Israel, along with North Korea, Cuba and India, as a "leading threat" to the infrastructure of U.S. financial and banking institutions.

The threats were listed in the NSA's 2007 Strategic Mission List, according to the document obtained by journalist/activist Glenn Greenwald, a founding editor of The Intercept, an online magazine that has a close relationship with Snowden, a former NSA and CIA contractor who fled the U.S. with thousands of top-secret documents last year.

In this new document, Israel was identified by the NSA as a security threat in several areas, including "the threat of development of weapons of mass destruction" and "delivery methods (particularly ballistic and nuclear-capable cruise missiles)." The NSA also flagged Israel's "WMD and missile proliferation activities" and "cruise missiles" as threats.